PROJECT SUMMARY/ABSTRACT Pediatric obesity is a public health crisis that is taking a dramatic toll on our nation's health and resources. Gold-standard treatment for pediatric obesity is family-based behavioral weight loss treatment (FBT). However, weight regain following FBT is common given the abundance of unhealthy prompts in the US obesogenic environment. The NIH has called for designing and testing interventions to achieve and maintain a healthy weight. Toward this end, two weight loss maintenance interventions were evaluated by Wilfley and colleagues in a randomized controlled trial of youth with overweight or obesity and their parents (NICHD R01 HD036904; Wilfley et al., 2007). Results showed that, following FBT, a social facilitation weight loss maintenance intervention (SFM) and a behavioral skills weight loss maintenance intervention (BSM) produced greater weight loss maintenance than a control condition, and SFM was superior to BSM. The critical next question is to examine which intervention strategy offers the greatest value. Thus, the overarching aim of this proposal is to evaluate the comparative cost-effectiveness of SFM, BSM, and the control condition for children and parents on changes in BMI units reduced over two years (Aim 1), depressive symptoms and binge eating behaviors reduced over two years (Aim 2), and on obesity-related health benefits and health care costs over 10 years (Aim 3). The microsimulation cost-effectiveness model will be based on a newly published approach from the largest economic evaluation of pediatric obesity interventions. Evaluation of the cost per changes in depression and binge eating is included because psychosocial changes from treatment have been neglected in prior cost-effectiveness analyses of pediatric obesity intervention, despite the impact of depression and binge eating on weight status, disability, and quality of life in youth with obesity. The proposed study and training plan enhances my program of research (a) evaluating the efficacy of behavioral interventions for obesity and weight-related issues, and (b) investigating factors that impact adoption and implementation of evidence-based behavioral interventions into routine practice. The rich educational environment of The University of Chicago will equip me with a strong theoretical and methodological foundation in cost-effectiveness analysis to conduct this translational research project and will expand my capacity to comprehensively evaluate behavioral interventions. Expertise of the mentorship team ensures this project will be successful. The goal of this work is to inform meaningful decisions regarding adoption of family- based weight loss maintenance strategies for the treatment of obesity, which has the potential to advance sustainable solutions for obesity care. In doing so, we facilitate efforts to ensure all individuals live healthy and productive lives. In summary, this NRSA would afford protected time for mentored postdoctoral training in cost- effectiveness analysis, which is critical for achieving my goal of being an independent investigator focused on testing, implementing, and increasing access to intervention delivery for obesity and weight-related issues.